Users of the social networking website "Facebook" circulated a video of the moment Russian President Vladimir Putin dropped the chair of Turkish President Recep Tayyip Erdogan at the trilateral summit with Iranian Rohani in the Russian city of Sochi.The video shows Russian President Vladimir Putin dropping the seat of his Turkish counterpart Recep Tayyip Erdogan on the ground, shaking hands before a joint press conference following the Sochi summit last week.Some videoconvers have described Putin's dismissal of Erdogan as insulting, especially since the relationship between Russia and Turkey has been strained since the killing of the Russian ambassador in Ankara and Turkey's destruction of Russian warplanes in Syria.The video